Mill for mixing caoutchouc



(No Model.)

G. WATKINSON. MILL FOB MIXING OAOUTOHOUG.

No. 525,638. Patented Sept.=4, 1894.

I Fzg.l [I

y wj Q UNITED STATES PATENT OFFICE.

GEORGE WATKINSON, OF COLCHESTER, CONNECTICUT.

MILL FOR M'IXING CAOUTCHOUC.

SPECIFICATION forming part of Letters Patent No. 525,638, datedSeptember 4, 1894.

Application filed September 22, 1893. Serial No. 486,183. (No model.)

To all whom it may concern:

Be it known that I, GEORGE WATKINSON, of Colchester, in the county ofNew London and State of Connecticut, have invented a new Improvement inMills for Mixing Caoutchouc, &c.; and I do hereby declare the following,when taken in connection with ac: companying drawings and the letters ofreference marked thereon, to be a full, clear, and exact description ofthe same, and which said drawings constitute part of this specification,and represent, in

Figure 1, a view in front elevation of one form which a mixing millconstructed in accordance with my invention may assume; Fig. 2, a viewin end elevation in the nature of a diagram, showing the three rolls.

Heretofore the mills employed for mixing crude caoutchouc orindia-rubber with the vulcanizing, adulterating or coloring compoundswhich are combined with it during the process of manufacture, havecomprised two hollow metal rolls, arranged in contact, or nearly incontact, and rotated toward each other. The mills have also containedmeans for driving and adjusting the rolls, steam and water pipes, andother accessories which are well known. In using the mills, the rubberhas been placed in the depression formed above and between the tworolls, and allowed to soften, and then to form itself around one ofthem. The vulcanizing, adulterating or coloring material has then beenplaced in the said depression above and between the rolls, and bypressure and attrition is gradually incorporated into the rubber, andwell mixed therewith, or kneaded thereinto. The incorporation of thesaid material with the rubber does not, however, take place at once, andconsiderable of the material drops down between the rolls, and has to bereturned again and again to the depression above them, until all of ithas been kneaded into the rubber, when the mixing process is complete.

.The object of my present invention is to save the time and laborrequired to return the escaping material to the rolls, and to make themixing process more speedy by enlarging the kneading capacity of themill.

With these ends in view, my invention consists in providing the millwith an auxiliary 'rolllocated below the two main rolls, and arranged tointercept the material falling between them, and to press it upward andgrind it into the mass of rubber revolving upon one of them.

In carrying out my invention, I employ a mixing-mill of any suitableconstruction, which it is unnecessary to detail because they are wellknown. To such a mill I add an auxiliary roll A, located centrally, orvery nearly centrally below the front and back main rolls '3 and B,which are arranged nearly in contact, or with only a narrow spacebetween them, in a horizontal plane, and geared so as to rotate towardeach other. The auxiliary roll A, is arranged in contact with the mainroll B, and geared so as to rotate in the opposite direction therefromor toward the roll B. As shown in Fig. 1 of the drawings, the threerolls are mounted in two uprights C C, and driven from a driving-shaftD,

j ournaled in the lower portions of the said uprights, and provided atone end with a small gear E, meshing into a large gear F, secured to oneend of the bearing or journal of the roll B, which is provided with asmall roll G, meshing into a corresponding roll H, carried by theauxiliary roll A. The opposite end of the front roll B, is provided witha gear G, corresponding in size to the gears G and H, and meshing into acorresponding gearcarried by the back roll B, but not shown. Adjustingscrews I I, mounted in the upper ends of the uprights, provide foradjusting the rolls.

The other details of the mill are those gener-' ally employed, and donot need description or illustration.

The operation of my improved mill will be understood by reference toFig. 2 of the drawings, in which the rubber J, is shown as formed uponthe main roll B, while a body K, of loose, vulcanizing, adulterating orcoloring material is represented as located in the depression above andbetween the rolls B and B. A portion K, of this material is also shownto have dropped down between the rolls B and B into the space formedbelow and between the same, and above the auxiliary roll A, whichcatches the said material as it falls, and forces it upward, and worksit into the rubber revolving with the roll B.

It will thus be seen that the material dropping between the main rollsis automatically returned to the rubber, and that the mixing capacity ofthe mill is enlarged by the mixing action of the auxiliary roll, whichdoubles the mixing capacity of the mill, as it supplies a second pointof contact for the kneading process, the rolls B and B having contact ata, and the rolls A and B having contact at a.

I would have it understood thatI do not limit myself to constructing themill in any particular manner, my invention comprehending broadly theuse of an auxiliary roll located below the two main rolls in position toco-operatetherewith as described, in interceptin g the material fallingdown between them and returning it to that one of the main rolls onwhich the rubber is being carried.

I am aware that a prior patent shows a rubber sheeting or grindingmachine, having a series of rolls arranged one above the other, so thatas the rubber drops between the upper pair of rolls it is caught byanother pair of rolls and passed through them, after which it is droppedupon another roll, which coacts upon one of the rolls of the pair aboveit to again grind the rubber. I do not, therefore,

broadly claim a rubber-making machine having more than two rolls,arranged so that the I by a narrow space from the roll B and toromaterial falling between a pair of rolls is 30 caught and acted uponagain.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

The herein-described mill for mixing caout- 35 chouc, comprising twomain rolls B and B, t; arranged in the same horizontal plane with a verynarrow space between them, and geared to rotate toward each other, andan auxiliary roll arranged below the rolls B and B' so an to catch thematerial falling between them, r and so as to be in contact orsubstantially in contact with the roll B, and to be separated l,

tate in opposite direction from the roll B but .5; toward the roll B,substantially as set forth, w

and whereby the material falling between the rolls is caught by theauxiliary roll, by which it is pressed upward and ground into the w massof rubber revolving on the roll B. 50 In testimony whereof I have signedthis specification in the presence of two subscribing witnesses.

GEORGE WATKINSON.

Witnesses:

LILLIAN D. KELsEY, FRED O. EARLE.

